ML20096C726
| ML20096C726 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 01/12/1996 |
| From: | Dennis Morey SOUTHERN NUCLEAR OPERATING CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9601180220 | |
| Download: ML20096C726 (9) | |
Text
Southern Nucl2ar Optrating Company post Othc3 Box 1295 Bemingham. Alabama 35201 Tel: phone (205) 868 5131 L
Southern Nudear Operating Company Dave Morey Vice President Farley Project January 12, 1996 the southem electnc system Docket Nos. 50-348 10 CFR 50.55 50-364 4
U. S. Nuclear Regulatory Commission ATfN: Document Control Desk Washington, D. C. 20555 Joseph M. Farley Nuclear Plant Request for Use of Altemative Rules For Post Repair / Replacement Hydrostatic Testmg for ASME Class 1. 2. and 3 Systems Based on ASME Code Case N-416-1 Ladies and Gentlemen:
In accordance with the provisions of 10 CFR 50.55a(a)(3)(i), Southern Nuclear Operating Company (SNC) proposes the performance of alternative tests and/or exammations in lieu of the hydrostatic pressure test currently required by the American Society of Mechanical Engineers j
(ASME)Section XI after repairs by welding on the pressure boundary or the attachment of replacements by welding. SNC proposes to implement the alternative rules of ASME Section XI, Code Case N-416-1 dated February 15,1994, entitled " Alternative Pressure Test Requirement for
)
Welded Repairs or Installation of Replacement Items by Welding, Class 1, 2, and 3,Section XI, I
Division 1." 'Ibe alternative rules will continue to provide an acceptable level of safety and quality equivalent to that provided by the ASME Code.
SNC requests using the altemative as it will allow the performance of system leakage tests following maintenance and modification activities in lieu of hydrostatic pressure tests which will result in a net benefit for the plant. Undue hardships are generally encountered with the performance of hydrostatic testing. Since hydrostatic test pressures are higher than normal operating pressures, this type of testing frequently requires significant effort to set up and perform.
Additionally, the need for special equipment and valve lineups can cause the testing to impact refueling outage schedules. Consequently, implementation of the alternative testmg provisions of ASME Code Case N-416-1 can reduce personnel radiation exposure, outage schedules, and costs.
SNC is requesting to adopt the alternative rules of Code Case N-416-1 using the NDE requirements of the 1971 edition with summer 1971 addenda of ASME Section III Code and system leakage test requirements of the 1983 ASME Section XI Code currently committed to by FNP instead of the 1992 editions referenced in the Code Case. SNC has reviewed the code editions in question and finds no appreciable differences in the areas ofint : rest to this relief request. The use of the 1992 edition would require modifying numerous plant, vendor and subcontractor procedures for administrative or editorial reasons only.
9601180220 960112 PDR ADOCK 05000348 0 li P
PDR 0
180041
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U. S. Nuclear Regulatory C=Wa ion Page 2 SNC understands that certam utihties have been required to include a root pass liquid grei.nt exam (PT) on all class 3 welds as an additional requirement to the ASME Code Case N 416-1 requirements SNC believes that this additional NDE is inennaistemt with existing ASME Section III exanunation requirements. Requiring a root pass PT on all class 3 welds imposes more stringent requiremcats on certain class 3 welds than on sundar class 2 mids. For example, class 3 socket welds (>2 "- 1992 code) will require both a root pass PT and a final PT whereas sinular class 2 socket welds only require a fmal PT. SNC also questions the usefulness of the root pass PT on all types of welds as a rehable means of h+iag potential crack initiatmg weld root conditions such as lack of fusion, incomplete penetration and root concavity or convexity. SNC beheves that the imposition of the additional NDE on the class 3 welds pmsents a hardslup wluch does not result in a compensating increase in the level of quahty or safety. SNC is therefore requestmg the adoption of the alternative rules of the code case without any additional class 3 NDE requirements.
~Ihe Rehef Requests and Code Case N-416-1 are attached for Nuclear Regulatory Commission (NRC) staff review. NRC approval is requested by March 13,1996, in order to support activitics associated with the 1996 Fall Unit 2 Refueling Outage, which is scheduled to begm in September, 19%.
Should you have any questions in this regard, please contact this office.
Respectfully Submitted, SOUTHERN NUCLEAR OPERATING COMPANY
{Y
&u Dave Morey EFB:maf CC416-lR. DOC
Enclosures:
- 1. Unit 1 Relief Request
- 2. Unit 2 Relief Request
- 3. ASME Code Case N-416-1 cc:
U. S. Nuclear Renulatory Cornmission. Washinnton. DC I
B. L. Siegel, Licensing Project Manager, NRR U. S. Nuclear Regulatory Comrnission. Region II S. D. Ebneter, Regional Administrator T. M. Ross, Senior Resident Inspector
FNP-1-M-043 RRLIFF REQUEST ENP-1 RR-47 COMPONENT OR RELIEF AREA:
All ASME Class 1,2, and 3 piping and components.
REQUIREMENT FROM WHICH RELIEFIS REQUESTED:
The 1983 Edition through Summer 1983 addenda,Section XI, IWA-4400(a) requires that a system hydrostatic test be performed in accordance with IWA-5000 after a welded I
repair on a pressure retaining boundary.
i BASIS FOR RELIEF: Reliefis requested from performing this Code required post repair / replacement hydrostatic pressure test on Class 1,2, and 3 welds. Alternative examinations are proposed.
ALTERNATE EXAMINATION:
Alternative examinations delineated in Code Case N-416-1 may be performed in lieu of Code required hydrostatic tests.
These alternative examinations are as follows.
(1)
Perform nondestmetive examinations in accordance with the methods and acceptance criteria of the applicable subsection of the 1971 Edition with summer 1971 addendaofASME SectionIII.
(2)
Perform a VT-2 visual examination of the welds in conjunction with the system leakage test using the 1983 Edition with Summer 1983 addenda of ASME Section XI(IWA-5000).
(3)
The use of Code Case N-416-1 will be documented in the applicable owners data report (NIS-2).
Page1of3
1 FNP-1-M-043 RELIEF REQUEST.
FNP-1 RR-47 4
l i
JUSTIFICATION FOR THE GRANTING OF RRI.IRF:
i SNC has determined that hydrostatically testing post repair / replacement welds represents an undue hardship. Hardships are generally encountered with the performance of hydrostatic testing performed in accordance with the Code. For
)
example, since hydrostatic test pressure would be higher than nominal operating pressure, hydrostatic pressure testing frequently requires significant effort to set up i
and perform. The need to use special equipment and the need for individual valve l
lineups can caus the testing to impact refueling outage schedules.
Piping components are designed for a number ofloadings that would be postulated i
to occur under the various modes of plant operation.Section XI hydrostatic testing
?
only subjects the piping components to a small increase in pressure over the design pressure and, therefore, does not present a significant challenge to pressure boundary conditions. Accordingly, hydrostatic pressure testing is primarily regarded as a means to enhance leakage detection during the examination of components under pressure, rather than solely as a measure to determine the structural integrity of the components.
The ASME Subcommittee Working Group on pressure testing concluded that no additional benefit is gained by conducting the existing system hydrostatic tests in place of the alternate rules which require a leak test at nominal operating pressure.
The conclusion of the group was that hydrostatic testing does not necessarily verify structural integrity, and in fact, the slightly higher test pressures currently called for in the Code could result in operational difficulties as well as extended outages and increased costs.
Industiy experience has demonstrated that hydrostatic test pressures do not usually propagate an existing flaw into a through-wall leak. This experience indicates that leaks in most cases are being found when the system is at normal operating pressure.
This is largely due to the fact that hydrostatic pressure testing is infrequently performed, while system leakage tests at normal operating pressures are conducted a minimum of once each refueling outage for Class I systems, and each 40-month inspection period for Class 2 and 3 systems. In addition, leaks may be identified during system walkdc,wns by plant operators.
Page 2 of 3
FNP-1-M-043 RELIEF REQUEST FNP-1 RR-47 JUSTIFICATION FOR THE GRANTING OF RRY TRF: (ContinuM)
SNC has determined that the nondestructive examinations and their associated acceptance criteria provide assurance of the structural integrity of the weld. The proposed alternative examinations will provide reasonable assurance that unallowable flaws are not present in the subject welds. Consequently, an acceptable level of quality and safety will be achieved and public health and safety will not be j
endangered by allowing the proposed alternative examination in lieu of the Code i
requirement, Page 3 of 3
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FNP-2-M-068 RELIEF REQUEST FNP-2 RR-47 COMPONENT OR RELIEF AREA:
All ASME Class 1,2, and 3 piping and umpts.
REQUIREMENT FROM WHICH RELIEF IS REQUESTED:
'Ihe 1983 Editim through Summer 1983 addenda,Section XI, IWA-4400(a) requires that a system hydrostatic test be pu fu.w.cd in accordance with IWA-5000 after a welded repair on a pressure retauung boundary.
BASIS FOR RELIEF:
Reliefis requested from performing this Code required post repair / replacement hydrostatic pressure test on Class 1, 2, and 3 welds. Alternative examinations are proposed.
ALTERNATE EXAMINATION:
Alternative examinations delineated in Code Case N-416-1 may be performed in lieu of Code required hydrostatic tests.
'Ihese alternative examinations are as follows.
(1)
Perform nondestructive examinations in accordance with the methods and acceptance criteria of the applicable subsection of the 1971 Edition with Summer 1971 addendaofASME SectionIIL (2)
Perform a VT-2 visual examination of the welds in conjunction with the system leakage test using the 1983 Edition with Summer 1983 addenda of ASME Section XI(IWA-5000)
(3)
The use of Code Case N 416-1 will be h_!mented in the applicable owners data report (NIS-2).
Page1of3
i FNP-2-M-068
[
RELIEF REQUEST I
i FNP-2
)
RR-47 i
f JUSTIFICATION FOR THE GRANTING OF RELIEF:
b i
SNC has determined that hydrostatically testing post repairkeplacement welds 4
represents en undue hardship. Hardships are generally encountered with the performance of hydrostatic testing performed in accordance with the Code. For exa.nple, since hydrostatic test pressure would be higher than nominal operating
{
pressure, hydrostatic pressure tw g frequently requires significant effort to set up and perform. The need to use s;-.al equipment and the need for individual valve i
lineups can cause the testing to impact refueling outage schedules.
Piping components are designed for a number ofloadings that would be postulated to occur under the various modes of plant operation.Section XI hydrostatic testing j
only subjects the piping components to a small increase in pressure over the design
]
pressure and, therefore, does not present a signi6 cant challenge to pressere boundary conditions. Accordingly, hydrostatic pressure testing is primarily regarded i
as a means to enhance leakage detection during the examination of components l
under pressure, rather than solely as a measure to determine the structural integrity i
of the components.
The ASME Subcommittee Working Group on pressure testing concluded that no additional benefit is gained by conducting the exiating system hydrostatic tests in place of the alternate rules which require a leak test at nominal operating pressure.
The conclusion of the group was that hydrostatic testing does not necessarily verify structural integrity, and in fact, the slightly highc-test pressures currently called for in the Code could result in operational difficulties as well as extended outages and increased costs.
Industry experience has demonstrated that hydrostatic test pressures do not usually propagate an existing flaw into a through-wall leak. This experience indicates that leaks in most caso are being found when the syt, tem is at normal operating pressure.
This is largely due to the fut that hydrostatic pressure testing is infrequently performed, while system k:akage tests at normal operating pressures r.re conducted a minimum of once each refueling outage for Class I systems, and each 40-month inspection peric <l for Class 2 and 3 systems In addition, leaks may be identified during system walkdowns by plant operators.
Page 2 of 3
FNP-2-M-068 RELIEF REQUEST FNP-2 RR-47 JUSTIFICATION FOR THE GRANTING OF RFI.TFF:
SNC has determined that the nondestructive examinations and their associated acceptance criteda provide assurance of the structural integrity of the weld. The proposed alternative examinations will provide reasonable assurance that unallowable flaws are not present in the subject welds Consequently, an acceptable level of quality and safety will be achieved and public health and safety will not be endangered by allowing the proposed alternative examination in lieu of the Code requirement.
4 Page 3 of 3
gg -
N-416-1 CASES OF AS%!E BOILER AND PRESSt RE \\ ESSEL CODE Approval Date: February 15.1994 See Numeric Indes for esperatoon and any reaffirmation dates.
\\
Case N-4161 placement items by welding, a system leakage test may Alternative Pressure Test Requirement for Welded be used provided the following requirements are met.
Repairs or Installation of Replacement items by (a) NDE shall be performed in accordance with the Welding, Class 1,2 and 3 methods and acceptance criteria of the applicable Sub-Section XI, Division 1
.cction of the 1992 Edition of Section !!!.
(b) Prior to or immediately upon return to service, a
/nquiry: What attemative pressure test may be per-visual examination (VT-2) shall be performed in con-formed in lieu of the hydrostatic pressure test required junction with a system leakage test, using the 1992 Edi-by para. IWA-4000 for welded repairs or installation of tion of Section XI, in accordance with para. IWA 5000, replacement items by welding?
at nominal operating pressure and temperature.
(c) Use of this Case shall be documented on an NIS-2 Form.
Reply It is the opinion of the Committee that in lieu if the previous version of this case were used to defer of performing the hydrostatic pressure test required by a Class 2 hydrostatic test, the deferred test may be elim-para. IWA-4000 for welded repairs or installation of re-inated when the requirements of this revision are met.
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